Sash pulley brake



Sept 28, 1943. w. G. SMITH 2,330,391

, SASH PULLEY BRAKE Filed June 30, 1941 Patented Sept. 28, 1943 [a r 7 I 2,330,391

7 2,330,391 SJASHPULLEY BRAKE William G. Smith, Tarentum, Pa., assignor'to Pittsburgh- Plate Glass Company, Allegheny County, Pa., a corporation of Pennsylvania Applicationlune '30, 1941; Serial No. 400,546

. 3 Claims.

The present invention relates to'window constructions and more particularly to a sash pulley structure for use in conjunction with doublehung, vertically sliding windows.

One object of the invention is to provide a brake for a sash pulley in order to permit controlled movement of a window sash, the counterbalanced arrangement of which hasbeen disturbed by the addition thereto of an auxiliary glazed sash.

Other objects and advantages of the invention will become more apparent from the following detailed description of a preferred embodiment thereof.

Modern adoption of air conditioning in the building field has occasioned the development of multiple plate window units to reduce heat transmission through the glazed areas of buildings. The application of auxiliary glazed frames to the ordinary window sash would appear to be a simple matter, but it results in a rather difficult problem aside from the question of installation. The additional weight of the auxiliary frame disturbs the counterbalanced arrangement of the sash and window weight. Accordingly it is not only more diflicult to raise the insulated sash but also the sash will not stay in its elevated position. It is not possible to substitute a heavier counterbalancing weight because there is not sufiicient room in the Window frame.

Briefly stated, the present invention contemplates the addition of a braking device to the standard sash pulley in such manner that it will permit free rotation thereof in one direction but will automatically engage and retard rotation of the pulley in the opposite direction.

One form of the invention is shown in the accompanying drawing, wherein:

Figure 1 is a front elevational view of a double-hung vertically sliding window construction to which the invention is applicable. I

Figure 2 is a fragmentary vertical sectional view, on an enlarged scale of the sash pulley structure showing the braking device in operative position.

Figure 3 is a side elevational view of the braking device; and

Figure 4 is an end elevational view of braking device.

Referring to the drawing, a window structure I includes a frame 2 positioned in a wall 3, and sashes 4 connected by cords 6 passing over pulleys 'l to counterbalance weights 8. The weights 8 lie within the frame 2 and are approximately of a size to compensate for the weights of the sashes the to which they are attached. This'portion of, the structure is conventionalfto most forms of double-hung vertically sliding windows; My invention is concerned primarilywith a; controldevice for the sash pulleys as shown in Figure 2. The pulleys I are secured upon horizontal axles H3 mounted within housings ll of metal from which extendflanges I2, which are fastened to the frame 2 by means of screws I4. The control device It comprises a brake-shoe l1 substantally of crescent shape with an enlarged base portion which fits within a flanged guide- Way l9 secured to an angle bracket 20. A bolt 2| passes through the bracket and serves to maintain the shoe l'I within the guideway, which is slotted, as indicated at 22, to permit a lateral movement of the shoe H. The bracket 20 is secured to the lower portion of the pulley housing H in such manner that the brake-shoe l7 engages the pulley 1. In this position the shoe 11 also contacts the cord 6 passing over the pulley 1.

When the sash 4, bearing the additional weight.

of an auxiliary frame, is in an elevated position the cord 6 on the inner side of the pulley will be under tension. This tension will force the brakeshoe I! against the pulley l and prevent its rotation to lower the sash. The frictional engagement may, however, be overcome by the application of slight force to the sash and it may thus be lowered at will. Since the braking action is operative in one direction only, the sash may be raised in the normal manner. In raising the sash, the cord 6 isunder tension on the outside of the frame due to the window weight suspended thereon, but the cord on-the inside of the frame is fairly loose. Accordingly the brake is not forced against the pulley and rotation thereof is not impeded. In fact rotation of the pulley is accompanied by a movement of the brakeshoe away from the pulley. As soon as the weight of the sash is returned to the cord the brakeshoe is urged against the pulley and its rotation is halted.

The operation of the control device is entirely automatic. Its simplicity in construction and installation are also important factors favoring its adoption. o

It will atonce be apparent that various modifications in the nature and arrangement of the elements of my invention are possible without departing from the spirit thereof or the scope of the appended claims.

What I claim is:

1. In a window mountng including sash structween the support surface and the pulley, said support having means for guiding the shoe, on, the surface thereof, a portion of the brake shoe having an outer surface over which; thercableis; bulged for instituting the wedging "acti-on cr-the: shoe between the support surface and pulley response to movement of thecable over the, pul

ley in one direction.

2. In a window mounting including sashjstruce; turerand a counterweight of, less weight than the sash' structure, a cable connected to the counter: weight and sash, structure, a pulleyrotatable in the upper portion of the window mounting and having a cable trained thereover to support the sash structure on the cable in vertically movable relation whereby the sash structure tends to overbalance the counterweight, a brake shoe engageable with the lower portion of the pulley and having an extension disposed laterally of the pulley substantially along the surface thereof, said cable bearing against the shoe extension and normally pressing the latter against the pulley, and

'rneansparried by the mounting for rnovably supportingzthe shoe againstthelpulle'y;

3. A window sash brake construction for exerting one-way braking action upon a weighted cable-and-pulley unit comprising a brake support, and'a shoe having a brake surface curved to correspond su-bstantially to the curvature of the pulley and-movable on said support into wedging and: braking relation between the support and pulley, said support having means for guiding the shoe slidably thereon, said shoe having an outwardly projecting portion to bulge the cable outwardly adjacent the pulley and being responsive to the cable in one direction ofmovement of the latter to press thesh' einto-a Wedging and limit ing' relation to thelpulley;

a WILLIAM G. SMITH. 

